Civil Engineering: Radius of Relative Stiffness

Radius of Relative Stiffness in Cement Concrete Pavement

• The radius of relative stiffness (lll) is a critical factor in understanding the behavior of cement concrete pavements.
• Westergaard's formula for radius of relative stiffness is:
  l=[Eh312k(1−μ2)]1/4 l = \left[\frac{Eh^3}{12k(1-\mu^2)}\right]^{1/4} l=[12k(1−μ2)Eh3​]1/4
• This formula includes the following variables:
  • EEE: Modulus of elasticity of cement concrete (measured in kg/cm²).
  • μ\muμ: Poisson's ratio for concrete.
  • hhh: Thickness of the concrete slab (measured in cm).
  • kkk: Modulus of subgrade reaction (measured in kg/cm³).

Factors Dependent and Independent of Radius

• The radius of relative stiffness depends on:
  • Modulus of subgrade reaction (kkk).
  • Poisson's ratio of concrete (μ\muμ).
  • Modulus of elasticity of cement concrete (EEE).
• The radius of relative stiffness is not dependent on:
  • Wheel load; this shows that the structural response related to stiffness is not influenced by the load applied by vehicles.

Implication

• Understanding these dependencies can help in the design and analysis of pavement structures, ensuring adequate strength and stability.

This quiz covers the concept of radius of relative stiffness in cement concrete pavement as per Westergaard's principles. It tests your understanding of the factors that influence this radius, including modulus of elasticity, Poisson's ratio, and more. Prepare to assess your knowledge on crucial civil engineering topics.